1. Field of the Invention:
The present invention is directed to electron field emission devices and to displays which incorporate electron field emission devices.
2. Description of the Prior Art:
Many types of non-thermionic (cold cathode) type field emitting devices have been disclosed in the prior art. Generally, an electric potential is applied near a pointed cathode in a vacuum to stimulate electron emission therefrom. U.S. Patents, such as: U.S. Pat. Nos. 3,921,022; 3,970,887; 3,998,678; and 4,095,133, illustrate fabrication techniques for field emitting devices utilizing evaporation and etching steps to form upwardly pointed cathodes and apertured accelerating electrodes on a flat surface. In the patents, materials, such as copper and silicon are used to form the cathodes since those materials are generally accepted as having good field emission characteristics. However, such materials erode after prolonged use and would not be suitable in display apparatus subjected to heavy use over prolonged periods of time. In addition, each of the devices disclosed in the aforementioned patents, requires constant application of voltage to the apertured accelerating electrode and its associated collector electrode to effect electron flow between the cathode and the collector. In a matrix type display device composed of a plurality of such field emitting devices, each accelerating electrode would necessarily require addressing for each scan period to maintain the display illumination.